Table 1. Characteristics of the study subjects by environmental tobacco smoke during pregnancy

1. Infant Phase I gene modify the effect of maternal exposure to environmental tobacco smoke on child behavior at two years of ageCJ Hsieh1, SF Jeng2, HF Liao2, KY Wu3, WS Hsieh4, YN Su4, PC Chen11National Taiwan University College of Public Health; 2National Taiwan University College of Medicine;3National Health Research Institutes, Taiwan; 4National Taiwan University Hospital In recently years, growing research had focused on tobacco smoke and behavioral problems. There are two major different behavioral problems: externalizing and internalizing. Previous studies show that smoking during pregnancy tends to increase risk of externalizing more than internalizing problems. The impact of maternal exposure to ETS on neurodevelopment is less clear. The aim of the study was to explore the modification effect of metabolic gene polymorphisms to maternal ETS exposure on children’s behavior problems at the two years of age. Background and Objective Results and Discussion Table 2 shows that only infant gene but not maternal gene related with child behavioral development including CYP1A1 MSPI andCYP1A1 Ile462Valgene. In table 3, ETS exposed group withCYP1A1 MSPI andCYP1A1 Ile462Val variant type have higher score of CBCL total score (p=0.011), externalizing score (p=0.011) and Aggressive score (p=0.011). It can be concluded that CYP1A1 Ile462Val and CYP1A1 MSPI metabolic genes can modify the effect of maternal exposure to ETS on early child behavior problems. Material and Methods Table 1. Characteristics of the study subjects by environmental tobacco smoke during pregnancy This study is one investigation of the Taiwan Birth Panel Study and a total of 198 pregnant women and their neonates were recruited between April 2004 and January 2005. We interviewed them by a structured questionnaire after delivery to obtain the information of maternal exposure to environmental tobacco smoke during pregnancy. Four metabolic genes, CYP1A1 MspI, CYP1A1 Ile462Val, GSTT1 and GSTM1 were identified from mother’s and infant’s DNA. Children’s behavior problems were measured through maternal report on the 99-item Child Behavior Checklist (CBCL) for age 1.5 to 5 years, which collects information on child behaviors occurring in the past 2 months at 2 years of age. The CBCL yields internalizing, externalizing and sleep scores to evaluate the behavior problems. The higher the score, the worse the behavior. We used multiple linear regression models to estimate the effects of ETS and gene modification on child behavior. Table 2. Multiple linear regression models of CBCL behavior problems at the age of 2 years by maternal exposure to environmental tobacco smoke, and each of metabolic gene polymorphisms. Table 3. Multiple linear regression models of CBCL by ETS exposure during pregnancy, and both metabolic gene polymorphisms. Conclusions Our study found that infant genes have modification effect for infant behavioral development but not maternal gene. In addition, this study demonstrates an obviously gene-environmental effect of maternal exposure to ETS on early children’s behavior problems including total, externalizing, and aggressive. In addition, both CYP1A1 Ile462Val andCYP1A1 MSPI metabolic genes could modify the effects. Corresponding author’s e-mail: pchen@ntu.edu.tw; First author’s e-mail: d94841007@ntu.edu.tw OMIH